In recent years, the researches as to introduce a fluid into microchannels for conducting the chemical reaction or generating microparticles are interested. Further, the development of the semiconductor manufacturing technologies, which are the gradually mature technologies, also facilitates the fabrication of the miniaturized fluid field channels and indirectly promotes the development of this filed. In the microfluidic chip, the application and control of the fluid play an important role in achieving the detecting purpose. The multiphase flows in the microfluidic chip, based on the differences in the geometrical shape or the subjected force, could make the continuous microdroplet emulsion formation have the applicable property that there is no interference among the phase interfaces. Therefore, the microfluidic chip is usually used in the fields of various chemical syntheses, biomedical detection, drug delivery, and so on.
Currently, most microchannels used in the microfluidic chip for generating microdroplets are two-dimensional (2D) channels. The structure of the microfluidic chip is more and more complex in response to the diversity of the problems to be solved. However, the repeatability and reliability of the data derived from the microfluidic chip decrease with the increased complexity of the channel structure design. For integrating more functions into the limited area on the chip, there is the need of simple channel structures with the simplicity in the fabrication and the practicality in the application for solving the problems that previously has to be solved by the complex structures.
In addition, in the known 2D cross channels made of poly(dimethylsiloxane) (PDMS), the process of generating the water droplet by using the oil as the continuous phase is easier owing to the hydrophobic property of the PDMS. In contrast, if the oil is used as the dispersed phase, the process of generating the oil droplet is hard due to the viscosity of the oil and the contacting angle with the channel wall.
For overcoming the mentioned problems, the novel droplet-generating method and device are provided in the present disclosure after a lot of researches, analyses and experiments by the inventors.